How to add a password to a PDF file on Mac OS X

If you have a PDF file that you want to keep private, you may consider encrypting it with a password so that users would have to enter that password before being able to view the contents of the PDF.
On Mac OS X, this is very easy to do.

Steps:

1. Open the PDF in Preview
2. Select "File" > "Export..."
   
   
   
3. In the "Save" dialog box, check the "Encrypt" checkbox.
   
   
   
4. Enter in the password, and verify it.
5. Press Save

That's all there is to it.

Video Tutorial